In the baseband processing system of the mobile communication terminal device, the conventional detection technology detects signals of one user while takes the signals of other users as noise. However, when the number of users increases, this method easily deteriorates the SNR so as to make the system performance and capacity undesirable. However, the joint detection technology fully uses all users' signals which cause the multiple access interference as well as the prior information of the correlated muitipath on the basis of the conventional detection technology and takes the user signal separation as a uniform correlated joint detection process, therefore it has better anti-interference performance and decreases the requirements of power control precision by the system. Therefore, this technology could use the uplink and downlink spectrum resource more effectively, thereby improving the system performance and increasing the system capacity significantly.
In the mobile communication baseband processing system of the TD-SCDMA terminal device, baseband processing algorithm of the joint detection is generally used and an important algorithm circuit, that is, the matched filter circuit, is always comprised in the joint detection.
As shown in FIG. 1, first, the serial interference cancellation module uses the Midamble sampling data of the destination cell in one time slot to cancel the serial interference coming from interference cells many times in turn to acquire a relatively accurate initial channel estimation result; meanwhile, the local spreading codes of the target cell are scrambled, rotated and conjugated to form composite spectrum spreading code in composite spectrum spreading code generation module; and then activation detection is performed on all candidate code channels according to the initial channel estimation result and composite spectrum spreading codes to determine finally which candidate code channels will be taken as the activated channels to join in the joint detection; second, the initial channel estimation result are post-processed to obtain the accurate channel estimation post-processing result; the channel estimation post-processing result and the composite spectrum spreading codes of the activated channels are convoluted to acquire the V vector in each activated channel; and then, the V vector is used to perform matched filtering on the data domain sampling data in a time slot to get the de-scrambled, de-spread, de-rotated, maximum ratio combined symbol data; the matched filter circuit sends the symbol data to a matrix operation module for canceling the inter-symbol and inter-channel interferences; the interference-cancelled symbol data are used as the final output result of the joint detection algorithm and sent to the symbol processing subsystem to implement the de-mapping process from the physical channel to transmission channel; and the de-mapping result is sent to the software for the afterwards task scheduling through the software and hardware interface.
However, the joint detection algorithm of TD-SCDMA system is of great algorithm complexity and requirement for the processing time is very strict. In view of cost and power consumption, the like of high performance software platform in the base station is hardly possible to be applied in the TD-SCDMA mobile terminals, therefore, a large number of hardware accelerators have to be designed for the TD-SCDMA mobile terminals in order to reserve enough processing time for the terminal software platform, which, however, must raise the cost for the complexity and is not practical as a result.
Moreover, the TD-SCDMA mobile terminal has to face higher requirement of operation speed by the hardware accelerator: for example, the spreading factor is 8 on uplink and 16 on downlink, one code channel is occupied on uplink and two code channels are occupied on downlink which are necessary in joint detection of the TD-SCDMA system at the case of 12.2kbps voice service. Take the matched filter operation whose spreading factor (SF) is 16 for example, the matched filter of the mobile terminal needs to matched filter 31 chip data in order to acquire one symbol that is de-spread, de-scrambled and completed channel compensation, and there are total 44 symbols in two data domain of one time slot in TD-SCDMA system need to be acquired in one code channel in the joint detection; this process has to be repeated for 16 times to acquire the symbols in 16 code channels, so as to complete the matched filter process of all code channels in one time slot, thus 31×44×16=21824 matching operations have to be performed.
It can be seen that having the high-speed matched filter circuit is very important to improve the operation efficiency of the TD-SCDMA baseband processing subsystem; however, the existing matched filter is generally implemented based on the baseband algorithm used in base station subsystem and since the pressure caused by cost of base station is much smaller than that of the mobile terminal side, for example, the base station side could apply high-performance software processer, which is hardly possible at mobile terminal equipments because of the cost; moreover, the hardware accelerator in the base station has less requirement of time and power consumption than the hardware accelerator in the mobile terminal has; therefore, the existing matched filter apparatus in the base station is too lack of generality to be applied directly in the terminal device.
Therefore, the prior art needs to be improved and developed.